Wet oxidation catalyst as well as preparation method and application thereof

Abstract

The invention provides a wet oxidation catalyst and a preparation method thereof, and a method for treating organic amine wastewater generated by reconstituted tobacco processing through catalytic wet oxidation. The wet oxidation catalyst comprises precious metal active components and a cerium oxide carrier, the cerium oxide carrier is of a porous structure, valence states of Ce in the cerium oxide carrier include positive tetravalence states, part of the precious metal active components are dispersed on the inner surface and the outer surface of the cerium oxide carrier, part of the precious metal active components are embedded into a framework of the cerium oxide carrier, and the cerium oxide carrier is of a porous structure. The valence states of the noble metal active component comprise a zero valence state and an oxidation valence state, and the content of the noble metal active component in the wet oxidation catalyst is 0.1-5% by weight. Due to the fact that precious metal ions are embedded into a cerium oxide carrier framework, interaction between cerium oxide and precious metal active components is stronger, the contact area is larger, active oxygen reaction sites can be provided more efficiently, and organic amine nitrogen substances such as nicotine in the reconstituted tobacco processing wastewater can be decomposed.

Description

Technical Field

[0001] The present application belongs to the field of catalyst technology, and specifically relates to a wet oxidation catalyst and a preparation method and application thereof. Background Art

[0002] Reconstituted tobacco technology is an advanced tobacco processing technology, but its production process produces a large amount of high-concentration organic wastewater that is difficult to biodegrade. The existing harmless treatment technology for reconstituted tobacco wastewater is mainly biological method, but the biological treatment efficiency of reconstituted tobacco wastewater is low due to biological toxic pollutants (nicotine, diene nicotine, etc.), and it takes a high cost and a long time to obtain wastewater that can meet the discharge standards. Catalytic wet oxidation method, as a new wastewater treatment technology, uses oxygen or air as an oxidant, and activates oxygen into hydroxyl radicals through the catalytic action of a catalyst, thereby completely oxidizing organic pollutants. It is very suitable for treating industrial organic wastewater with high COD concentration, but there is no research report on catalytic wet oxidation harmless treatment of organic amine industrial wastewater such as reconstituted tobacco wastewater. Summary of the invention

[0003] The invention provides a wet oxidation catalyst and a preparation method thereof, and a method for treating organic amine wastewater generated by reconstituted tobacco processing by using a catalytic wet oxidation method.

[0004] The first aspect of the present application provides a wet oxidation catalyst, which includes a precious metal active component and a cerium oxide carrier. The cerium oxide carrier is a porous structure. The valence state of the Ce element includes positive tetravalence. Part of the precious metal active component is dispersed on the inner surface and the outer surface of the cerium oxide carrier, and part of the precious metal active component is embedded in the skeleton of the cerium oxide carrier. The valence state of the precious metal active component includes a 0 valence state and an oxidized valence state. Calculated by weight percentage, the content of the precious metal active component in the wet oxidation catalyst is 0.1% to 5%.

[0005] In any embodiment of the first aspect, the cerium oxide support has a rod-like morphology.

[0006] In any embodiment of the first aspect, the content of the noble metal active component in the wet oxidation catalyst is 0.45% to 1.8% by weight.

[0007] In any embodiment of the first aspect, the noble metal active component includes one or more of Ru, Pt, Rh, Ir or Pd.

[0008] The second aspect of the present application provides a method for preparing a wet oxidation catalyst, which can be used to prepare any wet oxidation catalyst in the first aspect. The preparation method comprises: mixing a noble metal precursor, a cerium salt and water to obtain a first solution, wherein the first solution comprises metal ions, and the metal ions comprise Ce 3+and precious metal ions; mixing the organic ligand and the pH regulator to obtain a second solution; mixing the first solution with the second solution to allow the organic ligand and the metal ion to complex to obtain a catalyst precursor, the catalyst precursor comprising a metal organic framework material containing precious metal elements and cerium elements; sequentially performing oxidative roasting and reductive roasting on the catalyst precursor to obtain a wet oxidation catalyst.

[0009] In any embodiment of the second aspect, the molar ratio of the noble metal precursor to the cerium salt is 1:10000 to 1:5 based on the metal elements contained; preferably, the concentration of the cerium salt in the first solution is 10 mmol / L to 500 mmol / L.

[0010] In any embodiment of the second aspect, the precious metal precursor is a soluble salt, and the soluble salt includes one or more of platinum nitrate, palladium nitrate, rhodium nitrate, ruthenium nitrate, platinum chloride, palladium chloride, ruthenium chloride, iridium chloride, chloroplatinic acid, ammonium chloroplatinate, ammonium hexachlororuthenate, tetraamineplatinum (II) chloride, and nitrosodiammineplatinum.

[0011] In any embodiment of the second aspect, the cerium salt includes one or more of cerium nitrate, cerium sulfate, a hydrate of cerium nitrate, and a hydrate of cerium sulfate.

[0012] In any embodiment of the second aspect, the molar ratio of the cerium salt in the first solution to the organic ligand in the second solution is (0.05-5):1.

[0013] In any embodiment of the second aspect, the concentration of the organic ligand in the second solution is 5 mmol / L to 100 mmol / L; preferably, the organic ligand includes one or more of trimesic acid, terephthalic acid and 2-aminoterephthalic acid.

[0014] In any embodiment of the second aspect, the oxidative roasting is carried out in an atmosphere containing oxygen, the oxidative roasting temperature is 300° C. to 600° C. and / or the duration is 2 to 10 hours; preferably, the oxygen volume content in the above-mentioned oxygen-containing atmosphere is not less than 5%.

[0015] In any embodiment of the second aspect, the reduction roasting is carried out in a hydrogen-containing atmosphere, the temperature of the reduction roasting is 250°C to 600°C and / or the duration is 1 to 6 hours; preferably, the volume content of hydrogen in the above hydrogen-containing atmosphere is not less than 1%.

[0016] The third aspect of the present application provides a method for treating organic amine wastewater, which uses a catalytic wet oxidation method to treat the organic amine wastewater. The catalyst used in the catalytic wet oxidation method includes any one of the wet oxidation catalysts in the first aspect.

[0017] In any embodiment of the third aspect, the nicotine content in the organic amine wastewater is 100 ppm to 10,000 ppm, and the COD is 300 mg / L to 35,000 mg / L.

[0018] In any embodiment of the third aspect, the method for treating organic amine wastewater comprises mixing a wet oxidation catalyst with the organic amine wastewater, and performing a catalytic reaction for 1 to 6 hours at a temperature of 100° C. to 250° C. and an oxygen pressure of 0.5 MPa to 5 MPa.

[0019] In the wet oxidation catalyst of the present application, the porous structure of the cerium oxide carrier can generate oxygen vacancies through the transformation of the ion valence state, which plays an anchoring role on the particles or clusters of the precious metal active components. There are two possibilities for the location and state of the precious metal active components: either dispersed on the inner and outer surfaces of the cerium oxide carrier in a 0 valence state; or embedded in the skeleton of the cerium oxide carrier in an oxidized valence state. Because the precious metal ions are embedded in the skeleton of the cerium oxide carrier, the interaction between cerium oxide and the precious metal active components is stronger, and the contact area is larger, which can more efficiently provide active oxygen reaction sites, thereby helping to improve the catalytic activity of the catalyst in the wet oxidation catalytic reaction.

[0020] By using the wet oxidation catalyst provided in the present application, the wet oxidation reaction can be carried out under milder temperature and pressure conditions, and organic amine nitrogen substances such as nicotine can be more efficiently decomposed to obtain a better COD removal effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific embodiments of the present invention, the drawings required for use in the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 A scanning electron microscope (SEM) image of the wet oxidation catalyst prepared in Example 1 is shown, with a scale of 1.00 μm.

[0023] Figure 2 A transmission electron microscope (TEM) image of the wet oxidation catalyst prepared in Example 1 is shown, with a scale of 50 nm.

[0024] Figure 3 An H2-TPR (temperature programmed reduction) spectrum characterizing the properties of the oxide in the wet oxidation catalyst prepared in Example 2 is shown. DETAILED DESCRIPTION

[0025] The following embodiments further describe the implementation of the present application in detail. The detailed description of the following embodiments is used to illustrate the principle of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0026] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0027] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0028] As analyzed in the background technology of this application, there is no report in the prior art on harmlessly treating the high-concentration organic amine wastewater with biological toxicity generated during the processing of reconstituted tobacco leaves using catalytic wet oxidation technology, and there is also a lack of targeted and efficient catalyst products.

[0029] In the first embodiment of the present application, a wet oxidation catalyst is provided, which includes a precious metal active component and a cerium oxide carrier. The cerium oxide carrier is a porous structure. The valence state of the Ce element in the cerium oxide carrier includes a positive tetravalent state. Part of the precious metal active component is dispersed on the inner surface and the outer surface of the cerium oxide carrier, and part of the precious metal active component is embedded in the skeleton of the cerium oxide carrier. The valence state of the precious metal active component includes a zero valence state and an oxidized valence state. Calculated by weight percentage, the content of the precious metal active component in the wet oxidation catalyst is 0.1% to 5%.

[0030] The cerium oxide carrier of the present application is a porous structure, which can generate oxygen vacancies through the transformation of ion valence states, and play an anchoring role on the particles or clusters of the noble metal active components. There are two possibilities for the position and state of the noble metal active components in the wet oxidation catalyst: either dispersed on the inner and outer surfaces of the cerium oxide carrier in a 0 valence state; or embedded in the skeleton of the cerium oxide carrier in an oxidized valence state. In the wet oxidation catalyst provided by the present application, the interaction between cerium oxide and the noble metal active components is stronger because the noble metal ions are embedded in the skeleton of the cerium oxide carrier, and the contact area is larger, which can provide active oxygen reaction sites more efficiently, thereby helping to improve the catalytic activity of the catalyst in the wet oxidation catalytic reaction.

[0031] In the above wet oxidation catalyst, the valence state of the noble metal active component can be characterized by X-ray photoelectron spectroscopy (XPS), and the content of the noble metal active component can be determined by inductively coupled plasma-mass spectrometry (ICP-MS).

[0032] In some embodiments, the ceria support has a rod-like morphology. Figure 1The scanning electron microscope images of the wet oxidation catalysts in some embodiments of the present application are shown, and the cerium oxide carriers in the field of view are randomly distributed and present a rod-like morphology.

[0033] Precious metals have high chemical stability, good catalytic activity and generally high selectivity. In some embodiments, the precious metal active component in the wet oxidation catalyst includes one or more of Ru, Pt, Rh, Ir or Pd. The precious metal active component can be a single precious metal or can be composed of two or more precious metal elements.

[0034] The noble metal active component has a low electronegativity, can efficiently adsorb and activate oxygen molecules, reduce the reaction activation energy, and has excellent thermal stability and anti-poisoning ability. In some embodiments, the content of the noble metal active component in the wet oxidation catalyst is 0.45% to 1.8% by weight. The content of the noble metal active component is reduced, and the noble metal active component within the above range can further reduce the cost while obtaining higher catalytic activity.

[0035] The second embodiment of the present application provides a method for preparing the wet oxidation catalyst provided in any of the above embodiments. The method for preparing the wet oxidation catalyst comprises: mixing a noble metal precursor, a cerium salt and water to obtain a first solution, wherein the first solution comprises metal ions, wherein the metal ions comprise Ce 3+ and precious metal ions; mixing the organic ligand and the alkaline substance to obtain a second solution; mixing the first solution with the second solution to allow the organic ligand and the metal ion to complex to obtain a catalyst precursor, the catalyst precursor comprising a metal organic framework material containing precious metal elements and cerium elements; sequentially performing oxidative roasting and reductive roasting on the catalyst precursor to obtain a wet oxidation catalyst.

[0036] Metal organic framework (MOFs) materials are a type of crystalline porous materials with high specific surface area, high porosity and designable structure. They are composed of metal ions or metal clusters coordinated with organic ligands and have rich chemical adjustability. This application adopts a one-pot method to prepare a metal organic framework containing precious metal elements and cerium elements as a catalyst precursor, and the organic ligands and metal ions are complexed to form macromolecular insolubles. The characteristics of the metal organic framework are used to make the dispersion of the precious metal ions and cerium ions as high as possible. After oxidative roasting, the organic framework in the metal organic framework is burned off. During the burning process, the cerium ions form cerium oxide with a porous structure, and the precious metal ions are partially dispersed on the inner and outer surfaces of the cerium oxide carrier, and partially embedded in the skeleton of the cerium oxide carrier; after reduction roasting, the precious metal ions dispersed on the inner and outer surfaces of the cerium oxide carrier are reduced to a zero valence state.

[0037] In some embodiments, in order to make the raw materials react fully, the first solution can be added dropwise or streamed into the second solution, and stirring is performed during the dropwise or stream addition to make the two solutions evenly mixed. In some embodiments, the addition rate of the first solution during the dropwise or stream addition is 0.2 mL / min to 10 mL / min.

[0038] In some embodiments, the alkaline substance in the second solution includes a strong base such as NaOH or KOH, and the pH of the second solution is adjusted to ≥ 8 to dissolve the organic ligand more fully. In practice, the appropriate type of alkaline substance can be selected based on various factors such as the desired pH value and the composition of the catalyst to be prepared.

[0039] In some embodiments, the molar ratio of the precious metal precursor to the cerium salt used in the preparation process of the wet oxidation catalyst is 1:10000 to 1:5 based on the metal elements contained; preferably, the concentration of the cerium salt in the first solution is 10mmol to 500mmol / L, which is conducive to a more uniform dispersion of the active components.

[0040] In some embodiments, the noble metal precursor is a soluble salt, and the soluble salt includes one or more of platinum nitrate, palladium nitrate, rhodium nitrate, ruthenium nitrate, platinum chloride, palladium chloride, ruthenium chloride, iridium chloride, chloroplatinic acid, ammonium chloroplatinate, ammonium hexachlororuthenate, tetraamineplatinum (II) chloride, and diamine nitrosoplatinum.

[0041] In some embodiments, the cerium salt includes one or more of cerium nitrate, cerium sulfate, a hydrate of cerium nitrate, and a hydrate of cerium sulfate.

[0042] The type of organic ligand has a strong correlation with the topological structure of the metal organic framework, and the pore size and shape of the metal organic framework can be adjusted by selecting the organic ligand, and the pore size and shape will further affect the reaction path and product distribution. In some embodiments, the organic ligand is selected from one or more of trimesic acid, terephthalic acid and 2-aminoterephthalic acid.

[0043] In some embodiments, the molar ratio of the cerium salt in the first solution to the organic ligand in the second solution is (0.05-5): 1. The control of the above molar ratio can utilize the framework structure of the organic ligand to carry as much cerium salt and precious metal active components as possible.

[0044] In some embodiments, the concentration of the organic ligand in the second solution is 5 mmol / L to 100 mmol / L. The inventors have found through a large number of experimental studies that the organic ligand within this concentration range can further increase the rate of the coordination reaction and make the formed metal organic framework structure more stable.

[0045] In some embodiments, in order to avoid the influence of residual impurities and improve the efficiency of oxidative roasting, the catalyst precursor metal organic framework material is separated from the reaction solution, washed with water to remove surface impurities and residues, and then dried and oxidatively roasted to remove the organic part of the organic metal framework material. After oxidative roasting, the precious metal exists in an oxidized state. After subsequent reduction roasting, hydrogen is used under high temperature conditions to reduce part of the precious metal active components from the oxidized state to the metallic state, thereby obtaining a wet oxidation catalyst.

[0046] In some embodiments, in the wet oxidation catalyst preparation method, the oxidative roasting is carried out in an atmosphere containing oxygen, and the oxidative roasting temperature is 300°C to 600°C and / or the duration is 2 to 10 hours. Oxidative roasting under the above conditions is conducive to increasing its oxidative decomposition rate. Further, in some embodiments, the oxygen volume content in the above-mentioned atmosphere containing oxygen is not less than 5%, for example, it can be roasted in air.

[0047] In some embodiments, in the wet oxidation catalyst preparation method, the reduction roasting is carried out in a hydrogen-containing atmosphere, and the temperature of the reduction roasting is 250°C to 600°C and / or the duration is 1 to 6 hours. Reduction within the above temperature and time range further accelerates the kinetics of the reduction reaction, inhibits the agglomeration of the noble metal active components, and further optimizes the performance of the catalyst. Further, in some embodiments, the hydrogen volume content in the above hydrogen-containing atmosphere is not less than 1%.

[0048] The third embodiment of the present application provides a method for treating organic amine wastewater, which uses a catalytic wet oxidation method to treat the organic amine wastewater. The catalyst used in the catalytic wet oxidation method includes any one of the wet oxidation catalysts provided in the first embodiment of the present application.

[0049] Compared with the existing harmless biological treatment methods, the wet oxidation catalyst provided by the present application can completely oxidize the biotoxic pollutants in the organic amine wastewater, and has an excellent purification treatment effect. For example, the organic wastewater produced by the processing of reconstituted tobacco leaves contains high concentrations of biotoxic pollutants such as nicotine and diene nicotine. The wet oxidation catalyst provided by the present application can be used for catalytic wet oxidation to effectively remove the above pollutants. When the catalytic wet oxidation method is combined with the biodegradation technology, the catalytic wet oxidation method is used as a pretreatment, which can also greatly improve the treatment effect of the subsequent biological method.

[0050] In some embodiments, the nicotine content in the organic amine wastewater is 100ppm to 10000ppm, and the COD is 300mg / L to 35000mg / L. Nicotine is commonly known as nicotine, and its chemical formula is C 10 H 14N2 is one of the main alkaloids in tobacco. In the wastewater of reconstituted tobacco processing, the nicotine content is high. As a wastewater with a high organic amine content, its chemical oxygen demand COD is also high. When the wet oxidation catalyst of the present application is used to treat the above-mentioned organic amine wastewater, the nicotine decomposition efficiency is high.

[0051] Catalytic wet oxidation technology uses oxygen or air as an oxidant, activates oxygen into hydroxyl radicals through the catalytic action of the catalyst, and further completely oxidizes the organic pollutants. In some embodiments, the method for treating organic amine wastewater includes mixing a wet oxidation catalyst with organic amine wastewater, and performing a catalytic wet oxidation reaction for 1 to 6 hours at a temperature of 100°C to 250°C and an oxygen pressure of 0.5MPa to 5MPa. Under the action of the wet oxidation catalyst provided in the present application, the wet oxidation reaction can be carried out under the above-mentioned milder temperature and pressure conditions, more efficiently decomposing organic amine nitrogen substances such as nicotine, and obtaining a better COD removal effect.

[0052] The beneficial effects of the present application will be further illustrated below in combination with examples and comparative examples, but the scope of the present invention is not limited to these examples.

[0053] Unless otherwise specified, the raw materials used in the following examples or comparative examples are all commercially available products well known to those skilled in the art.

[0054] In the following examples and comparative examples, unless otherwise specified, simulated reconstituted tobacco wastewater is used as a representative system of organic amine wastewater to test the catalytic effect of the prepared wet oxidation catalyst. It has been determined that the initial nicotine content in the simulated reconstituted tobacco wastewater is 2000 ppm and the COD is 5400 mg / L.

[0055] In the following examples and comparative examples, in order to evaluate the catalytic effect of the catalyst, the nicotine content, COD and total nitrogen content of the simulated reconstituted tobacco wastewater after the catalytic reaction were measured respectively. Unless otherwise specified, the nicotine content was measured by high performance liquid chromatography, the COD was measured by potassium dichromate method, and the total nitrogen content was measured by ultraviolet spectrophotometry.

[0056] Example 1

[0057] In this embodiment, the preparation method of the wet oxidation catalyst includes the following steps:

[0058] Step 1: Dissolve 0.070 g of RuCl3·3H2O and 6.944 g of Ce(NO3)3·6H2O in 150 mL of pure water to obtain a first solution;

[0059] Step 2: dissolve 3.360 g of trimesic acid and 2 g of NaOH in 200 mL of pure water to obtain a second solution;

[0060] Step 3, adding the first solution dropwise into the second solution at 25° C. while stirring, the addition is completed in 150 minutes, stirring is continued for 6 hours, filtering and washing with pure water, and drying the obtained solid for 12 hours at a drying temperature of 80° C. to obtain a catalyst precursor, which is a metal organic framework material containing Ru and Ce elements;

[0061] Step 4: Place the catalyst precursor in a muffle furnace, calcine it in an oxygen-containing atmosphere at 400°C for 6 hours, then transfer it to a hydrogen-containing atmosphere and reduce it at 400°C for 2 hours to obtain a Ru / CeO2 catalyst. The physicochemical parameters of the catalyst are shown in Table 1.

[0062] Next, based on the catalytic wet oxidation technology, the catalytic oxidation effect of the above-mentioned Ru / CeO2 catalyst in treating organic amine wastewater was tested.

[0063] The specific test conditions are: 0.1g Ru / CeO2 catalyst is mixed with 10mL simulated recycled tobacco wastewater and placed in a high-pressure reactor for catalytic reaction. The catalytic temperature is 180°C, the oxygen pressure is 3MPa, and the reaction time is 2 hours.

[0064] Figure 1 The SEM image of the Ru / CeO2 catalyst prepared in this example is shown, with a scale of 1 μm. Figure 1 It can be seen that the wet oxidation catalyst has a rod-like morphology as a whole. Figure 2 Shows Figure 1 In the transmission electron microscopy image of the wet oxidation catalyst shown in , it can be more clearly observed that the cerium oxide support is rod-shaped and has a porous structure.

[0065] Example 2

[0066] In this embodiment, the preparation method of the wet oxidation catalyst is different from that of Embodiment 1 only in step 1:

[0067] Dissolve 0.144 g H2PtCl6·6H2O and 6.944 g Ce(NO3)3·6H2O in 150 mL pure water to obtain a first solution;

[0068] The remaining steps and operations are the same as those in Example 1 to obtain a Pt / CeO2 catalyst, wherein the mass percentage of Pt is 1.8%.

[0069] Next, based on the catalytic wet oxidation technology, the catalytic oxidation effect of the above-mentioned Pt / CeO2 catalyst in treating organic amine wastewater was tested.

[0070] The specific test conditions are: 0.1g Pt / CeO2 catalyst is mixed with 10mL simulated recycled tobacco wastewater and placed in a high-pressure reactor for catalytic reaction. The catalytic temperature is 180°C, the oxygen pressure is 3MPa, and the reaction time is 2 hours.

[0071] The H2-TPR (programmed temperature reduction) method was used to characterize the properties of the oxide in the wet oxidation catalyst of this embodiment. The H2-TPR spectrum is shown in FIG. Figure 3 As shown. A pure metal oxide has a specific reduction temperature, so this temperature can be used to characterize the properties of the oxide. If two oxides are mixed together and do not interact with each other during the TPR process, each oxide will still maintain its own reduction temperature. Based on this principle, Figure 3 The peak corresponding to 93°C represents the reduction of platinum oxygen species, the peak corresponding to 160°C represents the reduction of oxygen on the surface of cerium oxide near Pt, indicating that the platinum and cerium oxide of the wet oxidation catalyst have a large interface (contact surface) area, and the peak corresponding to 268°C represents the reduction of oxygen on the surface of cerium oxide away from Pt, indicating that the platinum metal ions in the cerium oxide skeleton are conducive to the transfer of oxygen species. It can be seen that the wet oxidation catalyst provided in the present application can more effectively utilize the oxygen on the surface of cerium oxide.

[0072] Example 3

[0073] In this embodiment, the preparation method of the wet oxidation catalyst is different from that of Embodiment 1 only in step 1:

[0074] Dissolve 0.023 g of PdCl2 and 6.944 g of Ce(NO3)3·6H2O in 150 mL of pure water to obtain a first solution;

[0075] The remaining steps and operations are the same as those in Example 1 to obtain a Pd / CeO2 catalyst, wherein the mass percentage of Pd is 0.45%.

[0076] Next, based on the catalytic wet oxidation technology, the catalytic oxidation effect of Pd / CeO2 catalyst in treating organic amine wastewater was tested.

[0077] The specific test conditions are: 0.1g Pd / CeO2 catalyst is mixed with 10mL simulated recycled tobacco wastewater and placed in a high-pressure reactor for catalytic reaction. The catalytic temperature is 200°C, the oxygen pressure is 3MPa, and the reaction time is 2 hours.

[0078] Example 4

[0079] In this embodiment, the preparation method of the wet oxidation catalyst is different from that of Embodiment 2 only in step 2:

[0080] Dissolve 2.656 g of terephthalic acid and 2 g of NaOH in 200 mL of pure water to obtain a second solution;

[0081] The remaining steps and operations are the same as those in Example 2 to obtain a Pt / CeO2 catalyst, wherein the mass percentage of Pt is 1.8%.

[0082] Next, based on the catalytic wet oxidation technology, the catalytic oxidation effect of the above-mentioned Pt / CeO2 catalyst in treating organic amine wastewater was tested, and the specific test conditions remained consistent with Example 2.

[0083] Example 5

[0084] In this embodiment, the preparation method of the wet oxidation catalyst is different from that of Embodiment 2 only in step 2:

[0085] 2.896 g of 2-aminoterephthalic acid and 2 g of NaOH were dissolved in 200 mL of pure water to obtain a second solution;

[0086] The remaining steps and operations are the same as those in Example 2 to obtain a Pt / CeO2 catalyst, wherein the mass percentage of Pt is 1.8%.

[0087] Next, based on the catalytic wet oxidation technology, the catalytic oxidation effect of the Pt / CeO2 catalyst in treating organic amine wastewater was tested, and the specific test conditions remained consistent with those in Example 2.

[0088] Example 6

[0089] In this embodiment, the preparation method of the wet oxidation catalyst is different from that of Embodiment 1 only in step 1:

[0090] Dissolve 0.007 g of RuCl3·3H2O and 6.944 g of Ce(NO3)3·6H2O in 150 mL of pure water to obtain a first solution;

[0091] The remaining steps and operations are the same as those in Example 1 to obtain a Ru / CeO2 catalyst, wherein the mass percentage of Ru is 0.1%.

[0092] Next, based on the catalytic wet oxidation technology, the catalytic oxidation effect of Ru / CeO2 catalyst in treating organic amine wastewater was tested.

[0093] The specific test conditions are: 0.1g Ru / CeO2 catalyst is mixed with 10mL simulated recycled tobacco wastewater and placed in a high-pressure reactor for catalytic reaction. The catalytic temperature is 220°C, the oxygen pressure is 3MPa, and the reaction time is 2 hours.

[0094] Example 7

[0095] In this embodiment, the preparation method of the wet oxidation catalyst is different from that of Embodiment 1 only in step 1:

[0096] Dissolve 0.028 g of RuCl3·3H2O and 6.944 g of Ce(NO3)3·6H2O in 150 mL of pure water to obtain a first solution;

[0097] The remaining steps and operations are the same as those in Example 1 to obtain a Ru / CeO2 catalyst, wherein the mass percentage of Ru is 0.40%.

[0098] Next, based on the catalytic wet oxidation technology, the catalytic oxidation effect of Ru / CeO2 catalyst in treating organic amine wastewater was tested.

[0099] The specific test conditions are: 0.1g Ru / CeO2 catalyst is mixed with 10mL simulated recycled tobacco wastewater and placed in a high-pressure reactor for catalytic reaction. The catalytic temperature is 200°C, the oxygen pressure is 3MPa, and the reaction time is 2 hours.

[0100] Comparative Example 1

[0101] This comparative example adopts an impregnation method, and the preparation steps include:

[0102] 0.072 g H2PtCl6·6H2O was dissolved in 3 mL pure water, and then 2.70 g CeO2 carrier was added, and the mixture was allowed to stand for 12 h and then dried to obtain a catalyst precursor;

[0103] The catalyst precursor was placed in a muffle furnace and calcined at 400° C. in an oxygen-containing atmosphere for 6 hours to obtain a Pt / CeO2 catalyst, wherein the mass percentage of Pt was 0.9%.

[0104] Next, based on the catalytic wet oxidation technology, the catalytic oxidation effect of the Pt / CeO2 catalyst in treating organic amine wastewater was tested, and the specific test conditions remained consistent with those in Example 2.

[0105] The physicochemical parameters of the catalysts of various embodiments and comparative examples were measured, and the results are shown in Table 1. For the sake of brevity, M is used to represent the noble metal active component in the table.

[0106] Table 1

[0107]

[0108] The evaluation of the catalytic oxidation effect of the catalyst on the simulated recycled tobacco wastewater is shown in Table 2.

[0109] The detection limit of nicotine is 0.1 ppm. The reconstituted tobacco wastewater in each embodiment is below the detection limit after treatment, which is not detected in Table 1.

[0110] Table 2

[0111]

[0112]

[0113] It can be seen from Table 2 that the nanorod-shaped catalyst provided in the present application can be used as a wet oxidation catalyst, and the precious metal nanoparticles loaded on the cerium oxide nanorods as active components can effectively catalyze the wet oxidation treatment of organic amine wastewater, efficiently decompose nicotine and other organic amine nitrogen substances in the wastewater, and reduce the chemical oxygen demand COD.

[0114] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A wet oxidation catalyst, characterized in that: The wet oxidation catalyst includes a precious metal active component and a cerium oxide carrier. The cerium oxide carrier is a porous structure. The valence state of the Ce element includes positive tetravalence. Part of the precious metal active component is dispersed on the inner surface and the outer surface of the cerium oxide carrier, and part of the precious metal active component is embedded in the skeleton of the cerium oxide carrier. The valence state of the precious metal active component includes a 0 valence state and an oxidized valence state. Calculated by weight percentage, the content of the precious metal active component in the wet oxidation catalyst is 0.1% to 5%.

2. The wet oxidation catalyst according to claim 1, characterized in that: The cerium oxide support has a rod-like morphology.

3. The wet oxidation catalyst according to claim 1 or 2, characterized in that: Calculated by weight percentage, the content of the noble metal active component in the wet oxidation catalyst is 0.45% to 1.8%.

4. The wet oxidation catalyst according to any one of claims 1 to 3, characterized in that The noble metal active component includes one or more of Ru, Pt, Rh, Ir or Pd.

5. The method for preparing a wet oxidation catalyst according to any one of claims 1 to 4, characterized in that: The preparation method comprises: The noble metal precursor, the cerium salt and water are mixed to obtain a first solution, wherein the first solution includes metal ions, and the metal ions include Ce 3+ and noble metal ions; mixing the organic ligand and the pH adjuster to obtain a second solution; The first solution and the second solution are mixed to allow the organic ligand to complex with the metal ion to obtain a catalyst precursor, wherein the catalyst precursor includes a metal organic framework material containing a noble metal element and a cerium element; The catalyst precursor is subjected to oxidation calcination and reduction calcination in sequence to obtain a wet oxidation catalyst.

6. The preparation method according to claim 5, characterized in that: The molar ratio of the noble metal precursor to the cerium salt is 1:10000 to 1:5 based on the metal elements contained; preferably, the concentration of the cerium salt in the first solution is 10 mmol / L to 500 mmol / L; Preferably, the noble metal precursor is a soluble salt, and the soluble salt includes one or more of platinum nitrate, palladium nitrate, rhodium nitrate, ruthenium nitrate, platinum chloride, palladium chloride, ruthenium chloride, iridium chloride, chloroplatinic acid, ammonium chloroplatinate, ammonium hexachlororuthenate, tetraamineplatinum (II) chloride, and diamine nitrosoplatinum; Preferably, the cerium salt includes one or more of cerium nitrate, cerium sulfate, a hydrate of cerium nitrate and a hydrate of cerium sulfate.

7. The preparation method according to claim 5 or 6, characterized in that: The molar ratio of the cerium salt in the first solution to the organic ligand in the second solution is (0.05-5):

1.

8. The preparation method according to any one of claims 5 to 7, characterized in that: The concentration of the organic ligand in the second solution is 5 mmol / L to 100 mmol / L; Preferably, the organic ligand comprises one or more of trimesic acid, terephthalic acid and 2-aminoterephthalic acid.

9. The preparation method according to any one of claims 5 to 8, characterized in that: The oxidation roasting is carried out in an atmosphere containing oxygen, the temperature of the oxidation roasting is 300° C. to 600° C. and / or the duration is 2 to 10 hours; Preferably, the oxygen volume content of the oxygen-containing atmosphere is not less than 5%.

10. The preparation method according to any one of claims 5 to 9, characterized in that: The reduction roasting is carried out in a hydrogen-containing atmosphere, the temperature of the reduction roasting is 250° C. to 600° C. and / or the duration is 1 to 6 hours; Preferably, the volume content of hydrogen in the hydrogen-containing atmosphere is not less than 1%.

11. A method for treating organic amine wastewater, using a catalytic wet oxidation method to treat the organic amine wastewater, characterized in that: The catalyst used in the catalytic wet oxidation method comprises the wet oxidation catalyst according to any one of claims 1 to 4.

12. The processing method according to claim 11, characterized in that: The nicotine content in the organic amine wastewater is 100ppm-10000ppm, and the COD is 300mg / L-35000mg / L.

13. The processing method according to claim 11 or 12, characterized in that: The treatment method comprises mixing the wet oxidation catalyst with the organic amine wastewater, and carrying out a catalytic reaction for 1 to 6 hours under the conditions of a temperature of 100° C. to 250° C. and an oxygen pressure of 0.5 MPa to 5 MPa.

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